(40 ILCS 5/17-133) (from Ch. 108 1/2, par. 17-133)
    Sec. 17-133. Contributions for periods of outside and other service.
    Regularly certified and appointed teachers who desire to have the following described services credited for pension purposes shall submit to the Board evidence thereof and pay into the Fund the amounts prescribed herein:
        1. For teaching service by a certified teacher in the
    
public schools of the several states or in schools operated by or under the auspices of the United States, a teacher shall pay the contributions at the rates in force (a) on the date of appointment as a regularly certified teacher after salary adjustments are completed, or (b) at the time of reappointment after salary adjustments are completed, whichever is later, but not less than $450 per year of service. Upon the Board's approval of such service and the payment of the required contributions, service credit of not more than 10 years shall be granted.
        2. For service as a playground instructor in public
    
school playgrounds, teachers shall pay the contributions prescribed in this Article (a) at the time of appointment, as a regularly certified teacher after salary adjustments are completed, or (b) on return to service as a full time regularly certified teacher, as the case may be, provided such rates or amounts shall not be less than $450 per year.
        3. For service prior to September 1, 1955, in the
    
public schools of the City as a substitute, evening school or temporary teacher, or for service as an Americanization teacher prior to December 31, 1955, teachers shall pay the contributions prescribed in this Article (a) at the time of appointment, as a regularly certified teacher after salary adjustments are completed, (b) on return to service as a full time regularly certified teacher, as the case may be, provided such rates or amounts shall not be less than $450 per year; and provided further that for teachers employed on or after September 1, 1953, rates shall not include contributions for widows' pensions if the service described in this sub-paragraph 3 was rendered before that date. Any teacher entitled to repay a refund of contributions under Section 17-126 may validate service described in this paragraph by payment of the amounts prescribed herein, together with the repayment of the refund, provided that if such creditable service was the last service rendered in the public schools of the City and is not automatically reinstated by repayment of the refund, the rates or amounts shall not be less than $450 per year.
        4. For service after June 30, 1982 as a member of the
    
Board of Education, if required to resign from an administrative or teaching position in order to qualify as a member of the Board of Education.
        5. For service during the 1986-87 school year as a
    
teacher on a special leave of absence with full loss of salary, teaching for an agency under contract to the Board of Education, if the teacher returned to employment in September, 1987. For service under this item 5, the teacher must pay the contributions at the rates in force at the completion of the leave period.
        6. For up to 2 years of service as a teacher or
    
administrator employed by a private school registered with or recognized by the Illinois State Board of Education, provided that the teacher (i) was certified under the law governing the certification of teachers at the time the service was rendered, (ii) applies in writing on or after the effective date of this amendatory Act of the 94th General Assembly and on or before June 1, 2009, (iii) supplies satisfactory evidence of the employment, (iv) completes at least 10 years of contributing service as a teacher as defined in Section 17-106, (v) pays the contribution required in this Section, and (vi) does not receive credit for that service under any other provision of this Code. The member may apply for credit under this subsection and pay the required contribution before completing the 10 years of contributing service required under item (iv), but the credit may not be used until the item (iv) contributing service requirement has been met.
        For each year of service credit to be established
    
under this subparagraph 6, a member is required to contribute to the System (i) 16.5% of the annual salary rate during the first year of full-time employment as a teacher under this Article following the private school service, plus (ii) interest thereon from the date of first full-time employment as a teacher under this Article following the private school service to the date of payment, compounded annually, at the rate of 8.0% per year.
    For service described in sub-paragraphs 1, 2 and 3 of this Section, interest shall be charged beginning one year after the effective date of appointment or reappointment.
    Effective September 1, 1974, the interest rate to be charged by the Fund on contributions provided in sub-paragraphs 1, 2, 3 and 4 shall be 5% per annum compounded annually.
(Source: P.A. 94-1111, eff. 2-27-07.)